I am trying to track down an error on boot up on our old forklift. We traced it down to a little black box connected to the main contactor. Bascily, right when you plug in the battery, the main contactor engages and this throws an error. If I remove the leads from the box that go to the contactor then the lift gets no power at all. I have the parts manual and there is nothing I can find in there about it and there are zero part numbers on the box itself. Going to post a pic in the replies of the box.

Thank you!